Improving background and star colour

[Epicycle]

Hi Ivo,

I've been trying to process the attached image with StarTools, but I'm not completely happy with the result, or perhaps I should say that
I'm not convinced I've made the most of the data. The details are:

-Megrez 72 @4.8 with WO flattener 6, Canon 1100D mod and Hutech LP filter
-Exposure: 40x 5m at iso1600
-Captured and stacked with Nebulosity

I feel I should be getting more out of over 3 hours. In particular, is there a way to improve the background and star colour? Here is a link to
the linear stack:

https://www.dropbox.com/s/r7pzd1wjj9h5v ... pforst.tif

Any tips on how to improve this are most welcome. Also, if you have a few minutes to spare, I would very interested to see your own rendition of the data and compare,

Thanks!

best
Epicycle

[admin]

Hi,

I'm still without broadband (tree fell on phone line a few days ago), I'll have a look at your data as soon as it comes back up again!
In the meantime, try the latest version of StarTools (1.3.2 and above) and in particular the improved Color module.
Use the Color module before switching off Tracking for best effect and follow the information/advice in the popups.
It is now much easier to find the right color balance and bring out color.

Again, I'll get back to you as soon as I can download your data!

[Epicycle]

Hi Ivo,

no worries! There's no rush at all for this. I'll try the latest version with the improved color module.
Thanks,
best
Epicycle

[admin]

Thanks for your understanding. Not having broadband is incredibly frustrating. It is even more frustrating to see Telstra (the national phone service) fiddle with the pole and cable day-in, day-out with no resolution!

[admin]

Hi Epicycle,

I finally got my broadband back and was able to download your data set.
This is what I came up with;

Epicycle_Markarian.jpg (341.53 KiB) Viewed 7429 times

All-in-all, not that different from your efforts, except perhaps for the color. The secret to that is using the Wipe module and the Color module.

This is what I did;

Autodev, to see what we have. I see a good bit of noise, some very sever vignetting/gradients. No stacking artefacts.
I bin to 50%.
To get rid of (most of) the vignetting I use the vignetting preset in Wipe, with Parameter [Aggressiveness] set to [86 %]
I redo the global stretch in the Develop module. Parameter [Digital Development] set to [97.57 %]
I use the Band module to get rid of some vertical banding in the image (dealt settings)
Next, I apply a little deconvolution (I use the new Decon preset in the Auto mask generator and invert and shrink x2 the result. Parameter [Radius] set to [2.5 pixels], Parameter [Regularization] set to [1.40 (smoother, less detail)]
Using the same mask, I apply some Wavelet Sharpening, Parameter [Scale 1] set to [2 %], Parameter [Scale 2] set to [3 %], Parameter [Scale 3] set to [53 %], Parameter [Scale 4] set to [100 %], Parameter [Scale 5] set to [100 %], Parameter [Mask Fuzz] set to [19.6 pixels], Parameter [Amount] set to [449 %], Parameter [Small Detail Bias] set to [97 %]
Now I do a final color calibration; Parameter [Cap Green] set to [To Yellow], Parameter [Bottom End Saturation] set to [1.00], Parameter [Top End Saturation] set to [4.10], Parameter [Saturation] set to [669 %], Parameter [Blue Ratio] set to [1.43], Parameter [Green Ratio] set to [1.00], Parameter [Red Ratio] set to [1.55]
Lastly I apply the Life Isolate preset and also run the Contrast module with default settings.
I finish off with switching Tracking off and applying some noise reduction; all scales set to 100%, Parameter [Color Detail Loss] set to [80 %], Parameter [Brightness Detail Loss] set to [50 %]
Just before saving, I bump up saturation a bit more using the Color module; Parameter [Bottom End Saturation] set to [2.60], Parameter [Top End Saturation] set to [Full], Parameter [Saturation] set to [224 %]

And that's it. Hope this helps!

[Epicycle]

Thanks Ivo! That's very useful indeed. Your version has quite a bit more color and detail than mine.
It's difficult to keep the noise down with a DSLR and long exposures. As for the vignetting, well... large sensor
and most likely my technique with flats is far from optimal...

The new color module is very user friendly now

best
Epicycle